On 1/10/22 18:36, Nicholas Piggin wrote:
Excerpts from Fabiano Rosas's message of January 8, 2022 7:00 am:
If MMIO emulation fails we don't want to crash the whole guest by
returning to userspace.
The original commit bbf45ba57eae ("KVM: ppc: PowerPC 440 KVM
implementation") added a todo:
/* XXX Deliver Program interrupt to guest. */
and later the commit d69614a295ae ("KVM: PPC: Separate loadstore
emulation from priv emulation") added the Program interrupt injection
but in another file, so I'm assuming it was missed that this block
needed to be altered.
Signed-off-by: Fabiano Rosas <farosas@xxxxxxxxxxxxx>
Reviewed-by: Alexey Kardashevskiy <aik@xxxxxxxxx>
---
arch/powerpc/kvm/powerpc.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index 6daeea4a7de1..56b0faab7a5f 100644
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -309,7 +309,7 @@ int kvmppc_emulate_mmio(struct kvm_vcpu *vcpu)
kvmppc_get_last_inst(vcpu, INST_GENERIC, &last_inst);
kvmppc_core_queue_program(vcpu, 0);
pr_info("%s: emulation failed (%08x)\n", __func__, last_inst);
- r = RESUME_HOST;
+ r = RESUME_GUEST;
So at this point can the pr_info just go away?
I wonder if this shouldn't be a DSI rather than a program check.
DSI with DSISR[37] looks a bit more expected. Not that Linux
probably does much with it but at least it would give a SIGBUS
rather than SIGILL.
It does not like it is more expected to me, it is not about wrong memory
attributes, it is the instruction itself which cannot execute.
DSISR[37]:
Set to 1 if the access is due to a lq, stq, lwat, ldat, lbarx, lharx,
lwarx, ldarx, lqarx, stwat,
stdat, stbcx., sthcx., stwcx., stdcx., or stqcx. instruction that
addresses storage that is Write
Through Required or Caching Inhibited; or if the access is due to a copy
or paste. instruction
that addresses storage that is Caching Inhibited; or if the access is
due to a lwat, ldat, stwat, or
stdat instruction that addresses storage that is Guarded; otherwise set
to 0.
